Based on the standard of the new-generation Avionics Digital Video Bus (ADVB), an airborne aeronautical chart assisting video transmission system was designed. In this paper, the ARINC 818 protocol is described in general. Then, the system design principle is presented according to the latest protocol standard. Finally, the detailed scheme for the auxiliary video transmission system of the electronic aeronautical chart is given. The system is designed with the modular and hierarchical design method. In this system, the protocol conversion of ARINC 818 is implemented by using FPGA, and the function of optical-electro, electro-optical conversion is realized through the optical module. The real-time HD avionics video data transmission is implemented with the video frame rate as 4.25 Gibit per second, and the resolution as 1920×1080P@60 Hz, 24 bit.The system design has been successfully applied to the integrated data management system onboard a certain type of modified aircraft, and has an important practical value.